Understanding Computers1 Chapter 5 System Software: Operating Systems and Utilities

Understanding Computers2 Overview This chapter covers: Differences between system software and application software Functions of and differences among operating systems Various types of operating systems Functions of and various types of utility programs A look at the possible future of operating systems

Understanding Computers3 System Software vs. Application Software System software acts as a mediator between application programs and the hardware resources of the computer system. Application software provides the tools to perform particular tasks on a PC, such as writing a letter, processing orders, playing games, composing an , and so forth.

Understanding Computers4 The Operating System A computer’s operating system is the collection of programs that manage and coordinate the activities of the computer system. Primary responsibilities are management and control. The operating system is the go-between, meshing the user’s application program with the resources of the system.

Understanding Computers5 The Operating System

Understanding Computers7 Functions of an Operating System Booting the computer and configuring devices. Interfacing with users. Managing and monitoring resources and jobs. File management. Security.

Understanding Computers8 File Management

Understanding Computers9 Processing Techniques for Increased Efficiency Multitasking—the ability of an operating system to work with more than one program (task) at a time. Multithreading—the ability to process multiple threads within a program at one time. Time-sharing—technique for multiple programs to share processing on a rotating basis.

Understanding Computers10 Processing Techniques for Increased Efficiency, Cont’d. Multiprocessing—the ability to use multiple CPUs to process multiple jobs. Parallel processing—the ability to use multiple CPUs to process a single job faster. Coprocessing—utilizing special processors for specialized chores (e.g. math coprocessor).

Understanding Computers12 Processing Techniques for Increased Efficiency, Cont’d. Memory management, such as the use of virtual memory. Buffering and spooling A buffer is an area in RAM or on the hard drive to hold input and output on their way in or out of system. The process of placing items in buffer so they can be retrieved by appropriate device is spooling.

Understanding Computers13 Differences Among Operating Systems Command line vs. graphical user interface. Personal vs. network operating systems. Types and numbers of processors supported.

Understanding Computers15 Operating Systems for Desktop PCs and Servers PC operating systems are usually designed for use on either: Desktop PCs (personal operating systems) Network servers (network operating systems) Some operating systems have versions for both; some personal operating systems have limited networking capabilities.

Understanding Computers16 DOS PC-DOS and MS-DOS were the dominant operating systems until the early 1990s. DOS traditionally used a command-line interface; it is not widely used today.

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Understanding Computers18 Windows Many versions of the Windows operating system have existed over the last several years. Windows 3.x (an operating environment over DOS, not an operating system). Windows 95 and Windows 98 (personal operating systems). Windows Me (personal operating systems for home PCs). Windows NT (network operating system).

Understanding Computers19 Windows, Cont’d. Windows 2000 (network and professional operating system). Windows XP (latest version that replaces both Windows 2000 and Windows Me for home and office PCs; based on Windows NT). Windows Server 2003 (latest network version). Windows Vista (?)

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Understanding Computers22 Mac OS Mac OS is the proprietary operating system used with Apple computers. Mac OS has a graphical user interface. The newest version is Mac OS X Version 10.3.

Understanding Computers24 UNIX UNIX is a commonly-used, high-end PC and server operating system. Not built around any one particular family of microprocessors—can be used on a variety of computers. Though traditionally a command line operating system, newer versions of UNIX use a GUI.

Understanding Computers25 Linux Linux is a version of Unix originally created in Linux is open-source software; has been collaboratively modified by volunteer programmers all over the world. Traditionally a command line operating system; many versions now use a GUI. Recent increased support from big name companies (Sun, IBM, HP, and Novell, for instance) has increased the use and support of Linux.

Understanding Computers27 NetWare One of the most widely used operating system on PC-based networks. NetWare provides a shell around the users’ local desktop operating systems so they can interact with network resources.

Understanding Computers28 Operating Systems for Handheld PCs and Mobile Devices Windows Embedded—designed for non-personal computer-based devices (e.g. cash registers). Windows Mobile—designed for handheld PCs, smart phones, and other mobile devices. Palm OS—designed for Palm handheld PCs. Symbian OS—designed for use with smart phones.

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Understanding Computers30 Operating Systems for Larger Computers Larger computers typically used operating systems designed specifically for that type of system. Many mainframes and supercomputers today are running Linux. A group of Linux PCs linked together to computer at supercomputing levels is called a Linux supercluster.

Understanding Computers31 Utility Programs Utility program—a type of systems program written to perform a specific system task, usually related to managing or maintaining the system. Many utilities are built into operating systems as well as being available as stand-alone programs. File management programs—allow you to look at and manage the files stored on your PC (copy, move, organize into folders, etc.).

Understanding Computers33 Utility Programs, Cont’d. Antivirus programs —find and eliminated computer viruses on your PC. Should be set up to run continuously and scan incoming files and messages. Should be set up to do a complete scan of your PC about once per week. Need to be updated on a regular basis.

Understanding Computers35 Utility Programs, Cont’d. Diagnostic programs — evaluate the computer system and make recommendations for fixing any errors found. Disk management programs — diagnose and repair problems related to the hard drive. Disk defragmentation programs rearrange the files on a hard drive to store them in contiguous locations to speed up performance.

Understanding Computers36 Utility Programs, Cont’d. Uninstall utilities remove programs from your hard drive without leaving bits and pieces behind. Programs should never be deleted from the hard drive without using an uninstall procedure, unless there is no other alternative. File compression programs make files smaller for archiving or sending over the Internet. Compression programs can both compress (zip) and decompress (unzip) files. Common programs are WinZip for Windows users and Stuffit for Mac users.

Understanding Computers38 Utility Programs, Cont’d. Backup utilities are programs designed to back up the contents of a hard disk. You can usually specify certain files or folders to be backed up or back up an entire drive. Businesses should back up frequently and regularly; individuals should back up their PC occasionally and all important files each time they are modified. Recovery utilities are designed to help you recover from a major computer problem, such as rolling back your hard drive to an earlier state if it quits working after you install a new piece of hardware or software.

Understanding Computers39 Utility Programs, Cont’d. Encryption programs are used to secure messages and files that are sent over the Internet or other networks; can also be used with individual files stored on a hard drive. Network and Internet utilities include: Performance monitors Logging programs Directory services or identity management programs Firewall programs Antispam and filtering programs

Understanding Computers40 The Future of Operating Systems Will likely continue to become more user-friendly. May eventually be driven primarily by a voice interface. Will likely be used to access an increasing number of Internet resources and applications, such as Web based software and services. Will likely continue to support more synchronization between an individual’s various computing devices, such as a desktop PC, handheld PC, and smart phone.

Understanding Computers41 Summary System software vs. application software The operating system Operating systems for desktop PCs and servers Operating systems for handheld PCs and mobile devices Operating systems for larger computers Utility programs The future of operating systems